1. Field of Invention
The invention relates to a heat exchanger of modular structure usable more particularly for heat exchanges between gases.
2. Description of the Prior Art
The applicant has already previously described different heat exchange devices of modular structure, for example, in the French published patent applications FR A 2 530 798 and 2 541 442. The devices described in these documents were formed of a stack of grids (or lattices) assembled one above the other by rabbeting, these grids being obtained by injection molding of the thermoplastic materials (metals or synthetic resins) or formed by assembling strips together, themselves obtained by machining or by injection molding different thermoplastic materials. When the strips or dividing walls forming the stacked grids had no perforations, according to a particular type of exchange structure, the said superimposed strips or dividing walls formed separate channels in which fluids taking part in the exchange, could flow, for example in alternate rows of channels, the fluids considered then flowing in parallel currents (in co-current or counter-currentwise).
In another type of exchange structure, some of the strips or dividing walls, in particular one of the strip or dividing wall assemblies disposed parallel to one another could also comprise perforations, creating between the channels of the same row communications allowing one of the fluids to flow in a direction substantially perpendicular to the strips or dividing walls thus pierced, so in a direction substantially perpendicular to that of the channels through which the other fluid flows. In this case, the exchanger could operate with crossed currents.
A particular embodiment described consisted of a three-block exchanger, comprising a central block with parallel currents (for example, counter-current) corresponding to a structure of the first type above and two end-blocks corresponding to a structure of the second type above and serving for the intake and the discharge of the fluids. The heat exchangers thus formed could be used more particularly for recovering heat by air introduced (and removed) laterally through the end-blocks in communicating channel networks, from the smoke which passed through the end-blocks through rows of separate channels. Another embodiment could consist of a single block corresponding to a structure of the second type above, such a structure being intended to operate with crossed currents.
New heat exchangers of modular structure have now been perfected whose constituent elements, consisting of plates having spacers which will be described further on are even easier to manufacture, for example by injection molding, than the grids (or lattices) forming the above described exchangers. Another advantage of the exchangers of the invention resides in the considerable reduction in the possibility of one fluid leaking to the other, as will be explained further on in the detailed description of the invention.